The current predicament of the Senate climate and energy proposal, which was attractive enough to lure the leaders of not only the Christian Coalition but also ConocoPhillips, Exelon and Duke Energy to a now-canceled bill launch Monday, underscores the fragility of its support.

The same political forces that have repeatedly shunted climate change to the back burner -- partisanship and its low rank on voters' priority list -- have made passing a bill a herculean task. It encountered another hurdle this weekend when Lindsey O. Graham (R-S.C.), one of its authors along with Sens. John F. Kerry (D-Mass.) and Joseph I. Lieberman (I-Conn.), said he was abandoning it unless climate legislation moved ahead of immigration on the Senate calendar.

For months, the three senators tried to assemble an inside-the-Beltway pact on climate change by reconciling the needs of the business and environmental communities. Now the fate of the bill rests on the prospects of a very different deal: one between Graham and Senate Majority Leader Harry M. Reid (D-Nev.), who sees immigration reform as more essential than energy to his reelection bid.

"I've got some political courage, but I'm not stupid," Graham said in an interview Saturday. "The only reason I went forward is, I thought we had a shot if we got the business and environmental community behind our proposal, and everybody was focused on it. What's happened is that firm, strong commitment disappeared."

By Sunday morning, Kerry and Lieberman -- who does not work on the Jewish Sabbath and therefore was not making calls until Saturday night -- were working on a rapprochement between Reid and Graham on energy legislation, called the American Power Act. White House chief of staff Rahm Emanuel called Graham over the weekend, while energy czar Carol Browner called Kerry and Lieberman, according to an administration official.

"He's assured me he'll do it before immigration reform, if it's ready," Lieberman said of Reid. "This certainly is not over, and to me, we've got a good bill."

In some ways, the problem that proponents of climate legislation face is that they're pursuing a policy goal that is not much of a hot-button political issue. Environmental activists had a well-attended event Sunday on the Mall, with musical stars Sting and John Legend, but immigration reform advocates are likely to dwarf that turnout with dozens of rallies across the country Saturday.

Sen. Sherrod Brown (D-Ohio), who spent months drafting language to protect the U.S. manufacturing sector as part of a climate deal, said he puts passage of the bill "on my list of top five priorities," especially since Ohio is helping lead the country in the production of jobs in the solar and wind industry. But when he goes home to his state to talk to constituents about the issues they care about most, "nobody talks about this. I never hear about it."

As a result, the bill's authors focused on doing what amounted to a legislative bank shot, lining up support among business interests the bill would impact, in an effort to get them to convince wavering senators to embrace the package. They held dozens of closed-door meetings with groups ranging from the American Gas Association to the National Mining Association and the Portland Cement Association, including one meeting this spring in which 30 officials from different business groups gave what one participant described as "their elevator pitch" for what they wanted in the bill.

"These three have gone out of their way to be engaging, to be constructive in listening," said Bruce Josten, executive vice president for government affairs at the U.S. Chamber of Commerce.

The senators doled out rewards to different groups in order to bring them on board, providing more free pollution allowances to the utilities sector, even if that meant less money to protect tropical forests overseas; ensuring that 37.5 percent of the revenue generated from new oil and gas drilling offshore would go to the coastal states closest to the drilling.

The horse trading infuriated some environmentalists -- Clean Air Watch president Frank O'Donnell said the bill "ought to be named 'Let's Make a Deal,' " -- but it helped neutralize some corporate opposition and brought on board influential backers such as the Edison Electric Institute and three of the nation's five biggest oil companies.

"It has the broadest support that's ever come together for an energy and climate bill before," Lieberman said, adding he is convinced several business leaders "will be our most effective advocates in convincing the undecided senators to get off the fence" in the weeks ahead.

Roberta Combs, president and CEO of Christian Coalition of America, said, "It doesn't make sense to move energy to the back burner in Congress when America is hemorrhaging oil money to nations that don't like us, and when so many families could benefit from jobs if we pursue a made in America energy plan."

Graham said he worried his colleagues were being "overly optimistic" in describing business support for the measure, and he lashed out at the decision by anonymous administration officials to tell Fox News earlier this month that they opposed the idea of a fee on the transport sector linked to the price of carbon, which quickly became labeled a gas tax. "I should have walked when I saw that story," he said.

An administration official, who asked not to be identified, said the White House and Graham simply had a difference of opinion on the issue, in part because the administration did not see winning the support of oil companies "as the holy grail" of climate and energy legislation.

After Graham's announcement, conservatives were quick to accuse him of seeking what Patrick Creighton of the conservative Institute for Energy Research called "an easy way out of being part of one of the most economically devastating pieces of legislation this country has ever seen, no more, no less."

But Graham, the one Republican who has been willing to work with Democrats on not only climate change but immigration and the closing of the detention facility at Guantanamo, just appears to be trying to limit the number of fronts on which he is confronting his party's leadership. And Kerry, who has had 270 individual meetings and phone calls with his Senate colleagues on the climate and energy bill, said Sunday he believes the key players can get past the "minor hiccup" of the latest climate skirmish.

"We're going to get this done," Kerry said, adding that administration officials "want this done, and they want it done next. But they also want to see we've got something real."

"I think we're on a good track," he said, adding that what might seem like inside deals to outsiders is just the legislative process. "You have to have meetings, you have to sit in the room and listen to them. That's representative democracy."

To do that, said the League of Conservation Voters' Gene Karpinski, the power brokers on Capitol Hill and in the White House will need to have a few more closed-door meetings.

"All of this needs to be resolved on the highest levels to bring it back together, which we see as both doable and necessary," Karpinski said.